You are acting like a 12 year old. She may have put it in her mailbox in the afternoon, just after the pick up. Where I live, pick up and delivery varies from about 4 p.m. until well after dark - 7 p.m. or later. That would mean it was not picked up until the following day - late in the day, after closing. So it was not processed until the following day, two days later. Updating tracking information is sporadic and often, once a week or more. It is costly. They can't do it every minute of every day. Also, packages can sit at the post office for 2 - 4 days before they are processed, if they are very busy. Your anger with the seller is inappropriate and unreasonable. You contracted to buy the item. A seller is not obligated to accept a return and refund you. It's their "choice". If you want to be angry at someone, be angry at yourself, for jumping the gun on an item that you did not want.
Certified Paralegal, with 25+ years' experience.